Photoacoustic apparatus

Abstract

A photoacoustic apparatus includes a light source, a probe including a reception element that receives a photoacoustic wave generated by a subject in response to being illuminated with light and output a time-series reception signal, a signal data acquisition unit that generates reception signal data based on the time-series reception signal and stores the resultant data, a light fluence acquisition unit that acquires a light fluence at a position of interest in the subject, and an information acquisition unit that acquires subject information based on the stored reception signal data, wherein in a case where the light fluence at the position of interest is smaller than a threshold value, the signal data acquisition unit reduces the amount of data for a part of the time-series reception signal that corresponds to the position of interest.

What is claimed is: 
     
         1 . A photoacoustic apparatus comprising:
 a light source;   a probe including a reception element configured to receive a photoacoustic wave generated by a subject in response to being illuminated with light from the light source and output a time-series reception signal;   a signal data acquisition unit configured to generate reception signal data based on the time-series reception signal output from the reception element and store the reception signal data;   a light fluence acquisition unit configured to acquire a light fluence at a position of interest in the subject; and   an information acquisition unit configured to acquire subject information based on the reception signal data stored in the signal data acquisition unit,   wherein the signal data acquisition unit generates the reception signal data and stores the generated reception signal data such that in a case where the light fluence at the position of interest is smaller than a threshold value, the amount of data is reduced for a part of the time-series reception signal that corresponds to the position of interest.   
     
     
         2 . The photoacoustic apparatus according to  claim 1 , wherein in a case where the light fluence at the position of interest is smaller than the threshold value, the signal data acquisition unit does not store a part of the time-series reception signal that corresponds to the position of interest. 
     
     
         3 . The photoacoustic apparatus according to  claim 1 , wherein
 the light fluence acquisition unit acquires the light fluence at a plurality of positions of interest, and   the signal data acquisition unit samples the reception signal corresponding to a position of interest where the light fluence acquired by the light fluence acquisition unit is smaller than the threshold value at a lower sampling frequency than a sampling frequency used to sample the reception signal corresponding to position of interest where the light fluence acquired by the light fluence acquisition unit is equal to or greater than the threshold value, thereby generating the reception signal data and the signal data acquisition unit stores the resultant reception signal data.   
     
     
         4 . The photoacoustic apparatus according to  claim 1 , wherein
 the probe includes a supporting unit configured to support a plurality of reception elements,   the supporting unit supports the plurality of reception elements such that directional axes of the respective reception elements converge in a particular region, and   the signal data acquisition unit generates the reception signal data and stores the generated reception signal data such that in a case where the light fluence at the position of interest is smaller than the threshold value and the position of interest is not included in the particular region, a part of the time-series reception signal that corresponds to the position of interest is subjected to the reduction in the amount of data.   
     
     
         5 . The photoacoustic apparatus according to  claim 1 , wherein
 the probe includes a supporting unit with a shape based on a sphere on a spherical surface of which a plurality of reception elements are supported, and   the signal data acquisition unit generates the reception signal data and stores the generated reception signal data such that in a case where the light fluence at the position of interest is smaller than the threshold value and the position of interest is not at the center of curvature of the shape of the supporting unit, a part of the time-series reception signal that corresponds to the position of interest is subjected to the reduction in the amount of data.   
     
     
         6 . The photoacoustic apparatus according to  claim 5 , wherein the signal data acquisition unit generates the reception signal data and stores the generated reception signal data such that in a case where the light fluence at the position of interest is smaller than the threshold value and the position of interest is not included in a high sensitivity region centered at the center of curvature of the shape of the supporting unit, a part of the time-series reception signal that corresponds to the position of interest is subjected to the reduction in the amount of data. 
     
     
         7 . The photoacoustic apparatus according to  claim 1 , wherein
 the light source generates light at each of a plurality of timings,   the reception element receives a photoacoustic wave and outputs the time-series reception signal at each of the plurality of timings,   the light fluence acquisition unit acquires the light fluence at the position of interest at each of the plurality of timings, and   the signal data acquisition unit generates the reception signal data, and stores the generated reception signal data, for each of the time-series reception signals respectively corresponding to the plurality of timings such that in a case where the light fluence at the position of interest is smaller than the threshold value, a part of the time-series reception signal that corresponds to the position of interest is subjected to the reduction in amount of data.   
     
     
         8 . The photoacoustic apparatus according to  claim 7 , wherein the light source generates light such that a condition of illuminating the subject with light is different among the plurality of timings. 
     
     
         9 . The photoacoustic apparatus according to  claim 7 , further comprising
 an optical system configured to direct the light emitted from the light source such that the light reaches the subject, and   an optical system moving mechanism configured to move the optical system such that the position of the optical system is different from one to another of the plurality of timings.   
     
     
         10 . The photoacoustic apparatus according to  claim 7 , further comprising a probe moving mechanism configured to move the probe such that the position of the probe is different from one to another of the plurality of timings. 
     
     
         11 . The photoacoustic apparatus according to  claim 1 , wherein
 the light fluence acquisition unit acquires the light fluence at a plurality of positions of interest, and   the signal data acquisition unit generates the reception signal data and stores the generated reception signal data at each of the plurality of timings such that in a case where the light fluence at the position of interest is smaller than the threshold value, a particular part of the time-series reception signal that corresponds to the position of interest is subjected to the reduction in amount of data.   
     
     
         12 . The photoacoustic apparatus according to  claim 1 , further comprising
 a control unit configured to set a measurement parameter associated with an illumination condition,   wherein the light fluence acquisition unit acquires the light fluence at the position of interest based on the measurement parameter set by the control unit.   
     
     
         13 . The photoacoustic apparatus according to  claim 12 , further comprising
 an input unit configured to allow input of the measurement parameter,   wherein the control unit sets the measurement parameter based on information associated with the measurement parameter output from the input unit.   
     
     
         14 . The photoacoustic apparatus according to  claim 1 , wherein the information acquisition unit does not acquire the subject information at the position of interest when the light fluence at the position of interest is smaller than the threshold value. 
     
     
         15 . A photoacoustic apparatus comprising:
 a light source;   a probe including a reception element configured to receive a photoacoustic wave generated by a subject in response to being illuminated with light from the light source and output a time-series reception signal;   a light fluence acquisition unit configured to acquire a light fluence distribution in the subject;   a data reduction determination unit configured to make a determination based on the light fluence distribution acquired by the light fluence acquisition unit as to a period in which the amount of data is to be reduced;   a signal data acquisition unit configured to generate the reception signal data, and store the generated reception signal data, such that the amount of data is reduced for a part of the time-series reception signal that is output from the reception element during the period; and   an information acquisition unit configured to acquire subject information based on the reception signal data stored in the signal data acquisition unit.